This made oscilloscope CRTs appealing to early computer-graphics pioneers, who pressed them into service as displays for things like radar defense networks. The beam's horizontal deflection can also be controlled with a second input voltage (called X-Y, or vector, mode). The printed circuit board has space for optional extras, such as a battery backup, and Wi-Fi and GPS modules for setting the time. The clock is driven by PIC microcontrollers and all the components are through-hole.Ĥ.
The clock can work on both 110- and 220-V power supplies selected via a jumper and can autodetect the frequency of utility AC power to use as a time base.ģ. A transformer and rectifier create the roughly 300 volts DC that the CRT requires. The kit will work with many different CRTs: You will need a lower voltage one designed for use in oscilloscopes. The kit does not come with a CRT, but you can purchase one from sites like eBay. Oscilloscope-type CRTs use two pairs of horizontally and vertically oriented plates located inside the tube to electrostatically deflect the beam: This approach was handy for oscilloscopes because an analog input voltage can control the vertical position of the beam directly (albeit filtered through some signal-conditioning circuitry), while an internal timing circuit controls the horizontal deflection, letting engineers see time-varying signals.ġ. TV-type CRTs use magnetic fields generated by coils located outside the vacuum tube to deflect an electron beam, which is scanned line by line across the screen to build up what's called a raster image. Oscilloscope-type CRTs are different from those found in televisions and most computer monitors.
The kit works with many CRTs that were designed to be used in oscilloscope-type displays and operated with relatively low voltages-in the range of hundreds, rather than thousands, of volts.Īs CRTs are becoming as unfamiliar to modern engineers as amplifier tubes did to the transistor generation, a quick recap of a few salient points is likely in order here. This attention-hogging accelerator was, of course, the cathode-ray tube (CRT), which reigned supreme as the electronic display technology for decades, before being unceremoniously relegated to the figurative and literal trash heap of history by flat-screen technologies.īut there are still CRTs to be found, and you can put some of them to great use with Howard Constantine's US $100 Oscilloscope Clock Kit. Engineers and scientists at their benches, and folks at home in their living rooms, would carefully arrange themselves to watch the dancing glow of a beam of subatomic particles smashing into a phosphorescent screen. Once upon a time, there was a type of particle accelerator so popular that it was mass-produced by the million.
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